There are several known test methods for determining various types of characteristics of hydrocarbon compounds, many of which are published by the American Society for Testing and Materials (ASTM). Many tests are directed toward determining the aromatic content of a liquid hydrocarbon, for example ASTM D2267-68 and ASTM D936-55 both test for aromatics in gasolines and ASTM D1017-51 tests for the presence of toluene and benzene. ASTM D875-64 (1968) and ASTM D1019-68 additionally test for the presence of olefins in petroleum distillates and ASTM D1319-70 tests for the presence of saturates, nonaromatic olefins and aromatics in petroleum fractions by fluorescent indicator absorption. Most of these tests are very long and involved, as an example, the D1319-70 test takes more than three hours to test one sample. Moreover, there is no direct correlation between the relative amounts of aromatics, olefins and saturates in a compound which allows one to predict the activity of the compound.
In the last few years, the environmental impact, e.g., potential toxicity and pollution problems, of known and new compounds has become of great interest and concern. In fact, the Federal Government and several state governments have promulgated regulations relating to the potential toxicity of compounds which are based on threshold limit values, e.g., the threshold amount of compound in terms of milligrams per cubic meter of air which will cause toxicity, and acceptable amounts of products which can be airborne based on the compound's photochemical activity. These values are generated for each specific chemical compound and chemical mixture and involve very time consuming techniques. Absent the specific testing of each hydrocarbon compound and hydrocarbon mixture, there is no way of predicting the toxicity or air pollution potential of any given hydrocarbon mixture.
It is known that hydrocarbons have the ability to be absorbed by rubber. For example, the ASTM D471-72 test for change in properties of elastomeric vulcanizates resulting from immersion in liquids does measure the change in weight or volume of the test elastomer specimen caused by immersion in a liquid. The purpose of the test, however, is to measure the effect of a particular liquid on a particular elastomer, not to measure the activity of the liquid. There has been no recognition that the phenomenon of absorption of a hydrocarbon by a rubber matrix may be used as a quantitative assay of a hydrocarbon compound which will enable one to predict the activity of the compound in a number of different circumstances. The present invention relies on this absorption phenomenon to determine the aromatic activity of a hydrocarbon which is predictive of a wide variety of chemical and/or physical activities of the hydrocarbon. Additionally, the test is fairly inexpensive, is applicable to liquid, vapor, solid and semisolid hydrocarbons and several samples can be run simultaneously in, for example, a three hour time period.